Artificial Teeth Selection for Complete Denture Construction PDF

Artificial teeth selection for complete denture construction Important Considerations ~ W W...

Artificial teeth selection for complete denture construction Important Considerations ~ W W - v Vertical and horizontal Y Form of dental arches. a Height of the Orientation of the occlusal plane. relations between the 3 Normal facial landmarks. occlusal plane. maxillary and mandibular casts. ~ W W v ~ - Nasolabial angle Corners of Philtrum of the Vermilion Nasolabial Mentolabial the mouth upper lip borders of the sulcus and fold sulcus upper and S lower lips angle formed by the two lines ~ passing through the lower Formed by - edge of the nose (the zygomaticus Variations in lip length, columella) and the edge of the muscles thickness, shape, and upper lip, normally mobility affect the approximately 90° visibility of upper and lower teeth. -buccinator (cheeks) -orbicularis oris (lipe) Muscle Support The cheeks and lips are made up of muscles: buccinator (cheeks) and orbicularis oris (lips) , both muscles need to be well supported by the flange of the denture. The teeth also support the muscles 7 upper lip rests on the labial surfaces of the upper anterior teeth 7 lower lip rests on the labial surfaces of the lower anterior teeth and incisal edges of the upper teeth. proper lips contour is achieved by reproduction of horizontal overlap between anterior teeth -  Incisal Guidance Angle - Formed by the path of the lower central incisor along the palatal surface of the upper central incisor, measured against the horizontal plane. Important for setting anterior teeth and constructing complete dentures. Guidelines from jaw relation for Teeth Setting W v v & - Orientation of the Proper lip support, Proper incisal Proper vertical Guidelines: occlusal plane during nasolabial angle, and show dimension of Midline, high lip the jaw relation step vermilion border how much of the incisors occlusion and line, canine lines. are visible at rest. centric relation - 2 Verified before teeth setting. & Provides proper lip support. Anterior occlusal plane Posterior occlusal RVD (Resting Vertical should be parallel to the plane should be Dimension) Helps select the correct interpupillary line. parallel to Camper's OVD (Occlusal Vertical S size of teeth and their line (ala-tragus line). Dimension) placement. FWS (Freeway Space): RVD - OVD = FWS Principles of Teeth Setting ↓ ↓ ↳ v ~ z - The vertical Inclination Harmony of Correlation of The selection of The horizontal artificial teeth orientation of anterior orientation of of anterior anterior esthetics and teeth. anterior teeth. teeth teeth incisal guidance Selection of upper anterior teeth according to the shape of the upper dental arch 1- Width: The upper six anterior teeth should extend to the corners of the mouth 2-Height: The smile line determines the height of the teeth.  2 Using pre-extraction S Diagnostic cast: Provides information about record the shape, size, height, and width of anterior teeth. S Photographs: Good quality photographs showing the upper six anterior teeth can be used for mathematical calculations of tooth width based on interpupillary width. determine the size S Radiographs: Can be used to measure tooth size, but may be distorted of the upper 6 ant and not reliable. S Extracted teeth: Provide good size information, but not shade information due to drying and color changes. & Photographs and casts of close relatives: Can provide good information for tooth selection. S Old dentures: Useful if the patient was satisfied with the size of the teeth in their previous dentures. S Aesthetic requirements X Post-extraction Tissue support guidelines Proper form, color & size - Position and orientation of anterior teeth Amount of upper anteriors show Functional requirements S Speech Stability (neutral zone) Position and orientation of anterior S Anatomical landmarks teeth Posterior teeth selection (anatomical, semi-anatomical, non- ~ - L anatomical) curpe/w/o Corners of the mouth Position of the canine Ala of the nose Harmony with the surrounding soft eminence or buccal V tissues frenum on the cast - Marks on the wax rim Harmony with the opposing Dental floss extended from the at rest indicate the occlusal surface M inner canthus of the eye, distal surface of the decide the position of the alongside the ala of the nose to canines. canine and determine the the upper wax rim, demarcates width of the upper six anterior the position of the cusp tips of the teeth. canines. Selection of Upper Six Anterior Teeth Criteria: Appropriately support the upper lip. Occupy the area of the upper anterior arch bordered by the corners of the mouth. Allow for individualization (rotation or spacing). 1)Support upper lip pantabbythecomer of a not Using Facial Proportions to determine the size - - ~ Berry's biometric index and pound's Anthropometric cephalic index: formula: Width of upper central incisor = Width of upper central incisor = Head circumference / 13 Bi-zygomatic / 16 The form of anterior teeth (square, tapering, or ovoid) should harmonize with the face b not be identical to it. I not identical Suggested guidelines (with no scientific basis): Y - The shape of the upper The shape of the upper central central incisor aligns incisor corresponds to the inverted - with the outline of the - shape of the face. - upper arch. - v U Leon William ( 1917) Classification of face Square arch = square anterior forms: 1.Square teeth, etc. z 2. Tapered 3. Ovoid Selection using face profile (in the sagittal plane): Straight: Forehead, base of the nose, and chin are in line Concave: Upper lip region protrudes. Convex: Chin protrudes and upper lip region retrudes.  Teeth selection according to sex Teeth selection according to Age: Older individuals: Teeth are often abraded with worn females : more rounded and less angulation. contacts, so contoured teeth may appear artificial. Males: incisal edges are more angular Tooth color darkens with age; bright teeth may seem unnatural and indicate dentures. Teeth selection according to Personality: Vigorous individuals: Larger, squarish teeth are preferred. Delicate individuals: Smaller, symmetrical teeth in a flat plane are recommended. Shade: Shade of teeth should blend with the face. Young people have lighter teeth, while older people have darker and opaque teeth. Smokers have discolored teeth due to stains. The color of the chosen teeth should be in harmony with the patient's complexion. The color of the face is more important than the teeth, as the teeth fall into the framework of the face. 3 Alveolar Ridge Anterior maxilla resorbs Resorption upwards and backwards. Amerior Maxilles : up + back Anterior mandible resorbs downwards and lingually. Amerios Mandible : down-lin This affects the position of artificial teeth. Maxillary anterior teeth are Anterior Teeth Maxillary are placed forward and inferiorly. placed forward + inferiorly Central incisors are 8-10 mm Factors Affecting - from the incisive papillae. Setting of Upper & Esthetics Lip support by the teeth. m Amount of tooth showing Teeth (about 2 mm). Length of upper lip affects the amount of show. eng Incisal third of central incisors - supports the lower lip. Phonetics Lower lip pressure can cause Speech is affected by the position of teeth and the contour and instability of the mandibular bulk of the palate. denture if placed anteriorly. m Incisal edges of upper anterior teeth should contact the junction of the oral mucosa and the transitional epithelium of the lower lip during gentle smiling and pronunciation of "f" and "v". & If teeth are too short (set too high), "v" will sound like "f". If teeth are too long (set too low), "f" will sound like "v". ⑤  Horizontal Orientation of Anterior Teeth Anteroposterior Position of Anterior Teeth Guides The lips should be supported to restore facial contours. pitte meise Maxillomandibular relationship influences the position of teeth (Class II and Class III). Follow the labial plate of the alveolar process. Upper central incisors are 8-10 mm in front of the - middle of the incisive papillae. A transverse imaginary line crossing cusp tips of upper canines should cross near the middle of the incisive papilla. Vertical Orientation of Anterior Teeth Depends on the length and mobility of the upper lip in relation to the dental arch. During a normal smile, the incisal and middle thirds are visible in all patients, while the cervical third is seen in 50%. Mandibular incisal third is visible in most patients. Older people, especially men, show more of their lower teeth. The incisal edge of the lower canine and cusp tips of lower first premolars are even with the lower lip at the corners of the mouth when the mouth is slightly open or at rest. Inclination of Anterior Teeth Affected by the inclination of the labial plate of bone. The profile form of the patient's face often reflects the natural anterior tooth inclination (concave profile = different inclination compared to convex profile). Remember the inclination of the osseous structures supporting the teeth.A Harmony in the General Composition of Anterior Teeth Harmony between incisal show and the patient's age. * Harmony of teeth with the smiling line of the lower lip (incisal edges of upper teeth follow the curvature of the line formed by the lower lip during smiling). * Harmony of the dental arch form after setting and the form of the residual ridge. Vertical positioning of upper canines is responsible for the shape of the smile D line.  Harmony of the Dental Arch Form and Form of the Residual Ridge : Square arch form Tapering arch form Ovoid arch form Central incisors are at a greater * Teeth are seldom rotated.* Central incisors are on a line distance forward from the canines. Show a greater amount of labial with the canines. D Rotation and lapping of the teeth surface. & Incisors should have little & rotation to give a broader effect. might be needed to accommodateD Have a curved appearance. * the shape of the arch. Selection of Posterior Teeth According to Lang, posterior tooth moulds are of four types: Anatomical Non-anatomical Zero-degree teeth Cuspless teeth Another classification of teeth according to their cusps: Cusp teeth: Teeth with anatomical cusps Cusp-less teeth: Flat occlusal surfaces Hybrid teeth: Combination between cusp teeth and cusp-less teeth Factors Affecting Selection of Posterior Teeth Stability factors Aesthetic factors Occlusal factors Cusped teeth can lock or cause tripping, potentially destabilizing If the patient only performs vertical mandibular - dentures. * Cusped teeth - movements during chewing, cuspless teeth may - Cuspless teeth are preferred for flat, atrophic mandibular ridges as tend to look suffice. - they do not create lateral forces and help stabilize the lower more natural, If the patient performs ruminatory (lateral) mandibular denture.* but require - movements, teeth with cusps are required for balanced The width of posterior teeth: appropriate - D > articulation and stable dentures. Too broad teeth can encroach on the tongue, leading to instability. length. - Examination of current dentures assists in the The number of posterior teeth is dependent on the mesiodistal Cuspless diagnosis: - length of the ridge. If insufficient length, consider dropping one teeth do not Evenly worn occlusal surfaces suggest vertical mandibular -premolar or one molar to maintain stability. allow for - movements. espress - General rule: Teeth should not be set on the retromolar pad area. & balanced - ~ Greater wear of maxillary buccal cusps suggests ruminatory articulation. - mandibular movements. -esps Hybrid Teeth Balanced occlusion possible, some grinding may be necessary. Balanced articulation possible if concepts like lingualised occlusion are used. Have a worn (attrited) appearance. Material of Teeth - v Porcelain Acrylic Teeth - - W - Disadvantages: Advantages: Disadvantages: Advantages: Needs mechanical retention (diatoric Greater resilience, Worn down Hard glazed surface holes and pins). cushioning with unaffected by abrasive Brittle and susceptible to fracture. supporting tissues consequent loss food. Different coefficient of thermal from occlusal loads. of vertical - Color stability. expansion from acrylic resin base Chemically united dimension. material, leading to crazing. with the denture Clicking noise. base resin. Arrangement (Setting) of Artificial Teeth Role of Occlusal Surface in Complete Denture Y -v -- Denture Stability Phonetics Facial Appearance Jaw Relations Chewing Guides Used for Setting Artificial Teeth Occlusion Rims: Five determinations for teeth setting: 1- Labial and Buccal Contours: Determine the buccolingual position of teeth. 2- Occlusal Plane: Customized in the patient's mouth, defines the occlusal - plane for setting. - - 3- Vertical Dimension: Establishes the vertical dimension of the wax rims. 4- Horizontal Relation:men Records the horizontal relation between the wax rims. - 5- Reference Lines: Midline, high lip line, and canine line provide reference points. - - Biometric Guides: Further refine tooth positioning.  Armamentarium Needed for Setting No. Instrument Description 1 Articulator (Average value articulator) Used to mount the casts and simulate jaw movements. 2 Mounted Master Cast with Wax Rims The base for tooth setting. 3 Set of Teeth (units: Upper Ant, Upper Post, Lower The artificial teeth to be set. Ant, Lower Post) 4 Benzene Burner Flame or Alcohol Torch Used to soften wax for tooth placement. 5 Wax Knife Used to carve and manipulate wax. 6 Lacron Carver Used to shape and refine tooth positions. 7 Occlusal Plane Guides the horizontal plane of occlusion. 8 Piece of Wax Used to secure teeth within the wax rim. 9 Ruler Used for measurements and alignment. 10 Pens Used for marking and labeling. Sequence of Setting 1- Maxillary Anterior Teeth: Central incisor, lateral incisor, canine, repeated on the opposite side. 2- Maxillary Posterior Teeth: First premolar, second premolar, first molar, second molar, repeated on the opposite side. 3- Mandibular Anterior Teeth: Set in the same sequence as maxillary anterior teeth. 4- Mandibular Posterior Teeth: Set in the same sequence as maxillary posterior teeth.  Teeth Labial View Profile ( lateral ) View Occlusal View Long axis slightly Long axis parallel Labial surface distally inclined. to the labial surface within the contour Mesial proximal of the wax rim (for of the wax rim, surface touches the lip support). continuous with the midline of the wax Neck slightly general contour (not Central rim (aligned with depressed in the exceeding or deep Incisor the patient's facial gingival third inside the wax). midline). (approximately Incisal edge parallel Incisal edge 10-15 degrees, to the wax contour. parallel and parallel to the Tooth slightly touching the inclination of the inclined distally, occlusal plane wax rim). following the wax contour. Long axis distally inclined more than centrals. Neck more depressed Continuous Incisal edge parallel to the than centrals, reflecting with the occlusal plane, contacting the smaller root size. central the distal surface of the incisor, Lateral central incisor. preserving Incisor Incisal edge raised 0.5 mm the contour from the occlusal plane (no of the wax touch). rim. neck will be slightly depressed in the gingival third. if we measure this inclination, it will be around 10-15 degrees Fits the corner of the Long axis vertical or arch. slightly distally Completely A line touches the inclined (less vertical, disto-buccal surface inclination than creating a of the canine, Maxillary centrals and prominent neck extending to define Canine laterals). or gingival the buccolingual Mesio-labial surface third. position of posterior continuous with teeth. anteriors; disto- Mesio-labial surface labial surface continues with continuous with anterior teeth, posteriors. preserving the contour of the wax rim  Maxillary canine: is a very important tooth to set, called the cornerstone of dental arch- -labial surface of the canine has two planes: 1-mesio-buccal 2-disto-buccal, and there is a line angle between them It fits the corner of the arch, there is a line touches the disto-buccal surface of canine, if we extend it will give the refrence of bucco-lingual position of posterior teeth -mesio-labial surface continues with anterior teeth with the contour of the wax rim, you should be aware of this point because we don’t want a flat setting called “Monkey appearance” Setting the Opposite Side Arch Symmetry: Each tooth should be similar in shape, size, and setting to its counterpart on the opposite side. Midline Alignment: A ruler perpendicular to the midline, touching the distal surface of the left canine, should intersect the distal surface of the right canine. Bonwill Triangle and Circle: Follow the established relationships to ensure proper positioning.  Maxillary Posterior Teeth Basic Occlusal Patterns Anatomic Teeth: Cusp inclination of 33 degrees. Semi-anatomic Teeth: Cusp inclination of 20 degrees. Nonanatomic Teeth (Cusp Less Teeth): Flat occlusal surface. Selection Criteria Well-Developed Alveolar Ridge: Anatomic teeth, providing high chewing efficiency. Resorption in Bone: Semi-anatomic teeth. Advanced Resorption or Negative Ridge: Non-anatomic teeth, minimizing chewing forces. Teeth Buccal View Profile View Occlusal View Long axis Both cusps in contact A line controls the perpendicular to with the occlusal plane buccolingual the occlusal (when both cusps are position, with the plane. well-developed). first premolar No contact Only the buccal cusp lingual to the line. between the touching the occlusal Premolar hidden Maxillary mesial surface plane (if the buccal behind the canine, First of the premolar cusp is larger than the preserving the Premolars and the distal palatal cusp). buccal corridor. surface of the Long axis Em canine (broken perpendicular to the contact of 0.5-1 occlusal plane, mm) avoiding neck decline. Set inside the A line, Both cusps touch similar to the first Long axis the occlusal plane premolar. Maxillary perpendicular (palatal cusp may Disto-labial surface of Second to the occlusal be slightly raised). the canine and the Premolars plane. buccal surface of the premolars aligned to a straight edge.  I'l A line controls the Tooth slightly buccal, Long axis mesially neck embedded in the buccolingual Maxillary inclined (neck wax with inclination. position, contacting First inclined mesially), Mesio-palatal cusp is the mesio-buccal Molars contributing to the the only cusp touching surface. anteroposterior the plane due to tooth Disto-buccal surface compensating inclination. curved towards the curve. palatal direction. B line touches the mesio-buccal and disto-buccal surfaces of the Maxillary first and second Second Long axis more mesially inclined than molars. Molars the first molar. Angle between A All cusps raised from the occlusal line and B line is plane, with the mesio-palatal cusp 5-10 degrees, closest to the plane preserving the buccal corridor. Buccal Corridor Width The difference between the visible maxillary dentition width and the inner lip commissure width.  Setting of Mandibular Artificial Teeth Arrangement of Mandibular Anterior Teeth Position: On or slightly labial to the mandibular ridge. Incisal Edge Relation: Lingual to those of the maxillary anterior teeth, slightly above the occlusal plane (creating overbite). Overjet and Overbite: Establish the horizontal (overjet) and vertical (overbite) relationships between the incisal edges. Incisal Guidance Angle: The angle formed by the line connecting the incisal edges of upper and lower anteriors and the occlusal plane (typically 15 degrees). Labial Lower 6 Anteriors Occlusal Plane Position: Above the occlusal plane (no more than 1 mm) to achieve overbite. Midline Coincidence: Aligned with the midline of the maxillary anteriors Axial Inclination: Centrals vertical, laterals distally inclined, canine more distally inclined. Equidistance Overjet Symmetry in the amount of overjet (avoiding a different amount of overjet in having 2mm overjet different areas). somewhere and touching in other No contact between upper and lower relation is teeth in centric occlusion (due to overjet). unacceptable.  ‫انتبه هون بال‬ Profile View lateral view Long Axis Inclination: Centrals (labially inclined), laterals (vertical), canine (lingually inclined). Arrangement of Mandibular Posterior Teeth Relationship to Maxillary Setting: Follows the maxillary setting, providing a harmonious relationship. Angle's Classification: Based on Class I occlusion (mesiobuccal cusp of upper first molar articulates with the buccal groove of the lower first molar). Setting on the Ridge Crest Defined by drawing a line indicating the crest of the ridge on the mandibular cast, extending it to the retromolar area and anteriorly. Lower First Molar: Position: Set based on Class I Angle's classification, considering the broken contact between the upper canine and first premolar (providing space).  Factors Influencing Balanced Occlusion Five factors play a crucial role in achieving balanced occlusion in complete dentures The guidance of the mandible by the 2 Condylar condyles during protrusive and lateral Guidance movements. Sagittal Condylar Guidance Angle: The angle formed between the inclination of the articular eminence and the horizontal plane. The only fixed factor, determined by the patient's anatomy. It can be compensated for by adjusting the remaining four factors. Sagittal Christensen Phenomenon: Factors for Teeth During protrusion, a V-shaped gap develops between the wax rims in the Separation posterior region. This gap is (Eccentric compensated for during tooth setting Movements) to achieve posterior balancing contact. Coronal (Transversal) Christensen Phenomenon: During lateral excursions, a V-shaped gap forms in the molar region on the non-working side due to the downward, forward, and inward movement. This gap is also I compensated for during tooth setting. Incisal guidance (anterior factor) The influence of anterior teeth contact on the mandible during protrusive movements. Incisal Guidance Angle: The angle formed between the occlusal plane and a line connecting the incisal edges of the maxillary and mandibular central incisors in the sagittal plane. This angle can be adjusted by modifying the vertical overlap and horizontal overlap. Increased horizontal overlap reduces the incisal guidance angle, while increased vertical overlap increases it. The incisal guidance angle should be smaller than the condylar guidance angle (same as average value articulator) for smooth mandible movement. This ensures edge-to- edge anterior relation without disocclusion of posterior teeth.  The relation between the incisal guidance angle of the setting of artificial teeth and the incisal guidance angle of the articulator is absolute parallelism. & Compensating Curves Curvatures in the occlusal surfaces of artificial teeth that compensate for the condylar paths during mandible movement. Anterio-posterior Curve (Spee): Compensates for the sagittal plane movement, theoretically preventing posterior separation. Lateral Curve (Wilson): Compensates for the coronal plane movement, theoretically achieving balanced occlusion by accommodating the balancing side's downward movement. Factors for Teeth Approximation S Cusp Angle The angle made by the slope of the cusp with a plane perpendicular to the tooth's long axis. L There are three basic occlusal patterns: Occlusal Plane Anatomic Teeth: 35° cusp angle. Semi-anatomic Teeth: 20° cusp An imaginary surface touching the incisal edges of angle. anterior teeth and cusp tips of posterior teeth. Nonanatomic Teeth: 0° cusp angle Considered semi-fixed; its inclination can be (flat). altered slightly to activate cusp angles, but it is Angulation of the Cusp: More constrained by the interpupillary line anteriorly important than cusp angle for and Camper's line posteriorly. balanced occlusion. In cases of steep condylar guidance angle, the occlusal plane inclination is increased by moving it upward posteriorly, along with increasing the compensating curves to achieve balanced occlusion.  Relationship Between Factors These factors are interconnected. For example, a steep condylar guidance angle can be compensated for by increasing the compensating curves, which indirectly increases the cusp angle. Alternatively, the incisal guidance angle can be decreased. The concept is to balance the factors like a scale, adjusting one factor to compensate for changes in another. balanced occlusion and articulation - static position dynamic movements Differences Between Natural Teeth and Complete Denture Teeth 1. Attachment to Supporting Structures: Natural Teeth: Retained in bony sockets by the periodontal ligament (PDL), which connects the teeth to the alveolar bone. Complete Denture Teeth: Attached to a mobile base resting on mucosa, with no PDL or similar attachment system. 2. Movement Under Occlusal Loading: Natural Teeth: Exhibit independent movement, with each tooth reacting individually to occlusal forces. Complete Denture Teeth: Move as a single unit; any occlusal load affects all the teeth simultaneously. 3. Balancing Contact (Non-Working Side): Natural Teeth: Balancing contact is considered pathological or deflective, as it interferes with smooth mandibular movement. Complete Denture Teeth: Balancing contact is essential to prevent the denture from tipping and to maintain stability.